The ability to determine the identity of an individual is a significant issue for security and personalization considerations. There are a variety of methods to make such a determination including facial recognition, signature authentication, password authentication, and device radio frequency identification (RFID). Each of these methods has limitations. Facial recognition requires prior knowledge of the person, a signature can be forged, passwords can either be forgotten or guessed, RFID devices (e.g., RFID key fobs) can become awkward to carry and can be lost.